Dating Siderian Palaeoproterozoic Glacial Deposits of the Kola Peninsula, Russia

Dating Palaeoproterozoic glacial deposits of the Fennoscandian Shield using detrital zircons from the Kola Peninsula, Russia

Authors:

Gärtner et al

Abstract:

New age constraints from detrital zircon U-Pb geochronology from clastic sediments and diamict deposits obtained maximum depositional ages for the Seidorechka and Polisarka Sedimentary formations of the Imandra-Varzuga Greenstone Belt of theKola Province, NW-Russia. These delimit the deposition of Palaeoproterozoic Huronian-age glacial deposits of the Fennoscandian Shield from c. 2430 Ma to less than 2411 Ma. The time constraint allows comparison to the first two of three possible glacial intervals recognized in the Huronian Supergroup, Canada, and South African diamict deposits. Intercontinental comparisons support these constraints, the assumption of a glacial origin of the diamictites and, further, the eventually global extent of the event.Similar age distributions and depositional ages of c. 2400 Ma within the Neverskrukk Formation of the Pechenga Greenstone Belt support a correlation with the Imandra-Varzuga Greenstone Belt succession, which was traditionally based on lithostratigraphic observations.

The detrital zircon age spectra of eight analysed samples show an Archaean dominance and reoccurring peaks around 2800-2750 Ma,which indicate similar origins for the zircons. Such peaks are corroborating with a major global crustal generation event being recorded in detrital zircon spectra worldwide. Additionally, certain age populations around 2440 Ma and 2500 Ma are present andindicate a correlation with intrusive magmatism that affected the region at that time and support a correlation based on overlapping age distributions